Bladed rotor

ABSTRACT

A turbomachine rotor of alternating bladed rings and spacer rings, the bladed rings including blades welded to a rim, a web extending radially inward from the rim, and flanges extending from both faces of the web, with a reinforcing ring of filament reinforced composite material serving to resist centrifugal forces on each flange.

United States Patent Joseph A. Wagle Indianapolis, Ind.

May 4, 1970 Oct. 5, 1971 General Motors Corporation Detroit, Mich.

lnventor Appl. No. Filed Patented Assignee BLADED ROTOR 5 Claims, 2Drawing Figs.

US. Cl 416/198, 416/218, 416/244 Int. Cl F0ld 5/30 Field of Search416/198 A, 218,213,244

lieferences Cited UNITED STATES PATENTS Stoffer et a1.

Palfreyman et a1. Howald Wagle Wagle Primary Examiner-Everette A.Powell, .1 r.

Attorneys-Paul Fitzpatrick and Jean L. Carpenter 416/230 X 416/230 X416/230 X 416/218 X 416/230 X ABSTRACT: A turbomachine rotor ofalternating bladed rings and spacer rings, the bladed rings includingblades welded to a rim, a web extending radially inward from the rim,and flanges extending from both faces of the web, with a reinforcingring of filament reinforced composite material serving to resistcentrifugal forces on each flange.

BLADE!) noron My invention is directed to improved structures ofturbomachine rotors, and particularly to a strong lightweight compositedrum rotor for turbomachines such as axial flow compressors and turbine.

The principal objects of my invention are to provide improvedlightweight rotor structures particularly suited to minimize and towithstand the centrifugal stresses arising from high-speed rotation, toprovide a readily assembled rotor structure particularly suited toadvantageously exploit the very high tensile strength of filamentreinforced composite materials; and to provide such a structureparticularly suited to modern techniques of fabrication.

Describing the preferred embodiment of my invention briefly, a rotor ismade up of a number of alternating bladed rings and spacer rings, thebladed rings having blades welded to the outer surfaces of the ring andhaving an inwardly extending web from which flanges extend in bothdirections axially of the rotor. These flanges are reinforced againstcentrifugal force by a ring of filament reinforced composite material.The spacer rings pilot the blade carrying rings radially and abut theflanges of the blade-carrying rings. Preferably, a spline arrangementbetween the spacer rings and blade-carrying rings provides fortransmission of torque through the rotor. The structure mayadvantageously employ a standoff ring" structure which forms part of thesubject matter of a prior patent application.

The nature of my invention and its advantages should be clear to thoseskilled in the art from the succeeding detailed description andaccompanying drawings of the preferred embodiment of the invention.

Referring to the drawings, FIG. I is a sectional view of a drum rotortaken in a plane containing the axis thereof, the end bells and shaftbeing shown somewhat schematically.

FIG. 2 is a greatly enlarged view of a portion of FIG. 1 illustratingmore clearly the subject matter of the invention.

FIG. 1 shows a rotor for a four stage axial flow compressor. The rotorcomprises a drum 2 made up of four bladed rings 3, five s acer rings 4alternating with the bladed rings 3, and two end bells 6 and 7. Asillustrated, the end bells are integral with stub shafts 8 and 10 bywhich the drum may be mounted for rotation in suitable bearings, stubshaft 10 having a driving flange 11. The parts 3, 4, 6, and 7 are heldtogether by a tie bolt or shaft 12 and a nut 14. The end bells may haveany suitable shape, depending upon the particular design. As shown, therotor drum progressively increases in diameter from its low pressure end(the left end as illustrated), but this also is a matter of design. Ingeneral, the stages of the compressor are as near alike as feasiblealthough they may differ in the length and chord of the blades and,ordinarily, the number of blades in the several stages.

Referring now to details of structure, each bladed ring 3 includes a rowof blades 15 of suitable airfoil section, which may be hollow asillustrated in FIG. 2. The blades 15 extend radially outward from acontinuous annular blade carrying ring 16, specifically from a rimportion 18 of the ring which extends axially of the rotor at least asgreat a distance as the axial projection of the chord of the base of theblade 15. The blades 15 are welded at their bases along the line 19 tothe rim by any suitable technique of welding, as, for example,ultrasonic spot welding. It is preferred for minimization of weight toeliminate any mechanical connection such as a dovetail between theblades and the blade carrying ring.

The rim portion 18 of the blade carrying ring is integral with a web 20which extends radially inward approximately at the midpoint of the axiallength of the rim and more particularly at the plane of the center ofmass of the bladed ring. The web 20 terminates in two axially extendingflanges 22, one extending forwardly and the other rearwardly from theweb 20. The radially outer surfaces of these flanges are cylindrical.Two reinforcing rings 23 of filament reinforced composite materialencircle the flanges 22 and serve to resist the centrifugal forcesdeveloped in the flanges and the forces transmitted from the blades andrim and web through the web to these flanges.

In most cases, a standoff ring 24 should be provided between the flanges22 and reinforcing rings 23 for reasons pointed out in my copendingpatent application, of common ownership with this application, Ser. No.823,608 for Turbomachine Rotor, filed May 12, 1969 now Pat. No.3,554,668. Briefly, the standoff rings are continuous or noncontinuouscorrugated or wavy spring rings which transmit force radially betweenthe parts 22 and 23 while permitting some relative growth between them.They are provided to compensate for the different elastic propertiesand, in some cases, different thermal expansion of the blade carryingring 16 and the reinforcing rings 23.

The rings 23 may be produced on a suitable mandrel and then shrunk orpressed in place over the flanges 22. They are retained by the spacerrings 4 at each side of the bladed ring 3. Each of these rings includesinwardly directed flanges 26 each with a radial face which bears againstthe spacer ring 23 and against the lateral face of a flange 22. Theflanges 26 bear at their inner coupling edges flanges 27 the edges ofwhich bear dog or spline teeth 28 between which fit drive dogs orsplines 30 extending from the inner surface of the web 20 and flanges22. These parts 28 and 30 provide an intermeshing spline arrangement forpositive transmission of torque between the parts of the rotor.Obviously, any other suitable torque carrying arrangement may be used.

The flanges 27 pilot within the inner surface of the blade carrying ring16 as indicated at 31 to align the successive bladed rings and spacerrings radially of the rotor.

In the preferred structure, the spacer rings bear circumferentiallyextending ridges 32 the outer margins of which closely approach theedges of the rim vl8, but with slight clearance. The rim bears inwardlyextending flanges 34 which closely approach the ridges 32.

The radially outer surfaces of the spacer rings 4 may cooperate with theinner shrouds of stator blade rows to minimize bypassing of the statorblade rows, as is well understood by those skilled in the art.

The first and last of the spacer rings 4; that is, those immediatelyadjacent the end bells 6 and 7 may be similar in structure to theintermediate spacer rings except that they have only one end tocooperate with a bladed ring. These may,

if desired, be integral with the end bells or may be coupled to the endbells through any suitable spline connection or other arrangement,including a welded connection.

The rotor structure described herein, although quite different in manyrespects from that of my prior application referred to above, isintended to employ the same types of lightweight high strength materialsaccording to the state of the art as it now exists or may develop in thefuture. The choice of materials will depend to some extent uponinstallation, particularly the temperatures involved. The presentlypreferred materials for the reinforced rotor described are titanium forthe blade rings and spacer rings and a carbon or boron filament andepoxy resin composite for the reinforcing rings 23. The standoff springsmay be of steel, and the end bells preferably of titanium.

It will be clear to those skilled in the art from the foregoing that therotor structure described is particularly suited to the minimization ofweight and to ready manufacture of a highspeed rotor structure.

The detailed description of preferred embodiments of the invention forthe purpose of explaining the principles thereof is not to be consideredas limiting or restricting the invention, as many modifications may bemade by the exercise of skill in the art.

lclaim:

l. A turbomachine rotor comprising, in combinat o bladed rings, spacerrings disposed between and abutting adjacent bladed rings, and meansretaining the bladed rings and spacer rings fixed together in abuttingrelation to form a drum rotor; each bladed ring comprising an axiallyextending rim bearing a ring of blades extending radially outward fromthe rim, a web integral with the rim extending radially inward from nearthe middle of the rim, a flange integral with the web extending axiallyfrom each face of the web, and a reinforcing ring of filament reinforcedcomposite material disposed around the outer surface of each flange.

2. A turbomachine rotor comprising, in combination, bladed rings, spacerrings disposed between and abutting adjacent bladed rings, and meansretaining the bladed rings and spacer rings fixed together in abuttingrelation to form a drum rotor; each bladed ring comprising an axiallyextending rim bearing a ring of blades extending radially outward fromthe rim, a web integral with the rim extending radially inward from nearthe middle of the rim, a flange integral with the web extending axiallyfrom each f cc of the web, and a reinforcing ring of filamentreinforcedv composite material disposed around the outer surface of eachflange; the flanges abutting the adjacent spacer rings.

3. A turbomachine rotor comprising, in combination, bladed rings, spacerrings disposed between and abutting adjacent bladed rings, and meansretaining the bladed rings and spacer rings fixed together in abuttingrelation to form a drum rotor; each bladed ring comprising an axiallyextending rim bearing a ring of blades extending radially outward fromthe rim, a web integral with the rim extending radially inward from nearthe middle of the rim, a flange integral with the web extending axiallyfrom each face of the web, and a reinforcing ring of filament reinforcedcomposite material disposed around the outer surface of each flange; theflanges abutting the adjacent spacer rings, and the spacer rings beingpiloted within the bladed rings.

4. A rotor as defined in claim 3 including also a torquetransmittingspline connection between the said flanges and the spacer rings.

5. A turbomachine rotor comprising, in combination, bladed rings, spacerrings disposed between and abutting adjacent bladed rings, and meansretaining the bladed rings and spacer rings fixed together in abuttingrelation to form a drum rotor; each bladed ring comprising an axiallyextending rim, a ring of blades extending radially outward from the rimand welded to the rim, a web integral with the rim extending radiallyinward from near the middle of the rim, a flange integral with the webextending axially from each face of the web, and a reinforcing ring offilament reinforced composite material disposed around the outer surfaceof each flange.

55 UNITED STATES PATENT OFFICE CERTEFICATE OF CORRECTION Patent No"Inventor(s) fioseph A. Wlgle that error appears in the above-identifiedpatent It is certified treated as shown below:

that said Letters Patent are hereby co and 001mm 1, after: the title,insert the follawing aragraph The invention herein described was madethe course 015 work under a contract or subcontract thereunder with theDepartment of Defense.

Signed and sealed this 2nd day of May 1972.

Attost:

ROBERT GOTTSCHALK Commissioner of Patents Attesting Officer

1. A turbomachine rotor comprising, in combination, bladed rings, spacerrings disposed between and abutting adjacent bladed rings, and meansretaining the bladed rings and spacer rings fixed together in abuttingrelation to form a drum rotor; each bladed ring comprising an axiallyextending rim bearing a ring of blades extending radially outward fromthe rim, a web integral with the rim extending radially inward from nearthe middle of the rim, a flange integral with the web extending axiallyfrom each face of the web, and a reinforcing ring of filament reinforcedcomposite material disposed around the outer surface of each flange. 2.A turbomachine rotor comprising, in combination, bladed rings, spacerrings disposed between and abutting adjacent bladed rings, and meansretaining the bladed rings and spacer rings fixed together in abuttingrelation to form a drum rotor; each bladed ring comprising an axiallyextending rim bearing a ring of blades extending radially outward fromthe rim, a web integral with the rim extending radially inward from nearthe middle of the rim, a flange integral with the web extending axiallyfrom each face of the web, and a reinforcing ring of filament reinforcedcomposite material disposed around the outer surface of each flange; theflanges abutting the adjacent spacer rings.
 3. A turbomachine rotorcomprising, in combination, bladed rings, spacer rings disposed betweenand abutting adjacent bladed rings, and means retaining the bladed ringsand spacer rings fixed together in abutting relation to form a drumrotor; each bladed ring comprising an axially extending rim bearing aring of blades extending radially outward from the rim, a web integralwith the rim extending radially inward from near the middle of the rim,a flange integral with the web extending axially from each face of theweb, and a reinforcing ring of filament reinforced composite materialdisposed around the outer surface of each flange; the flanges abuttingthe adjacent spacer rings, and the spacer rings being piloted within thebladed rings.
 4. A rotor as defined in claim 3 including also atorque-transmitting spline connection between the said flanges and thespacer rings.
 5. A turbomachine rotor comprising, in combination, bladedrings, spacer rings disposed between and abutting adjacent bladed rings,and means retaining the bladed rings and spacer rings fixed together inabutting relation to form a drum rotor; each bladed ring comprising anaxially extending rim, a ring of blades extending radially outward fromthe rim and welded to the rim, a web integral with the rim extendingradially inward from near the middle of the rim, a flange integral withthe web extending axially from each face of the web, and a reinforcingring of filament reinforced composite material disposed around the outersurface of each flange.